Roo killing hens 1x1

I have a roo that is very docile with me and my family (my dogs also), but for some reason he has started picking off my hens one by one. The first hen that died, I thought maybe something was wrong with it and the flock was helping nature along, but we finally caught my roo doing the deed. He has killed 3 now. It seems like he is picking on the weakest and picking picking picking until he is killing them. They are 17 weeks old. My roo is a brown leghorn and the hens are leghorns, orpingtons, and barred rock. He has killed a orpington and 2 barred rocks. We had to shoot one of the barred rocks yesterday because of the damage to her neck (muscle hanging out and flopping around), so I guess technically we killed her. They free range and have plenty of scratch, feed, water and space. None of the other hens have any sign of feather picking. It's just like he decides whick one has to go and tortures it until it dies. What to do what to do??? Any ideas? I LOVE my roo.. he has such a personality, he "talks" to me and is normally very docile...

If it was me and I wanted to keep the roo, I would make him his own little house and pen. You could still let him out to visit, when you can watch him. A lot of people make separate housing for breeding, broodies with their chicks, disabled chickens, picked on chickens or roosters.

I think y'all might be right. I hate to seperate him, but I obviously don't want him killing off hens either. I'd rather have him seperated and get to keep him. Do y'all think if I seperated him it would be temporary or forever?

Abouth the shooting, my hubbie did the shooting and she died right away. I'd never let something suffer.. the reason I had him shoot her in the first place.